STRUCTURE OF THE BLADDER WALL OF HUMAN FETUSES IN THE ANTENATAL PERIOD

Abstract

The aim - to study the histological structure of the bladder wall of human fetuses in the antenatal period. Material and methods. Microscopy and morphometry were performed to measure the thickness of the layers of the bladder wall of human fetuses at gestation period from 15 to 40 weeks. The specimens were stained with hematoxylin-eosin and according to Van Gieson. Immunohistochemical study was performed by indirect immunofluorescence and peroxidase technique, the following monoclonal antibodies were used: to detect the smooth muscle component - against Alpha Smooth Muscle Actin (α-SMA); to determine the degree of myocyte differentiation - against Desmin; to identify neurofilaments - anti-Neurofilament Monoclonal Antibody (NF), to detect the endothelial cells of the vascular wall - against CD31. Results. The thickness of the bladder wall in fetuses from the 15th to the 40th week of gestation increases by 3,5 times, the mucous membrane thickness - by 1,3 times, the muscular layer - by 9,8 times. It was found that the ratio of the layers of the muscular membrane of the bladder (inner: middle: outer) changed in different periods of gestation and was 1,1:1:1,2 at 15 weeks, 1:1: 1,5 by the 25th week, and 1:2,1:2,1 by the 40th week. The coefficient of proliferative activity of myocytes was developed, which reflected the growth rate of the detrusor layers and the morphological maturity of the cells of the bladder muscular coat for various periods of gestation. The coefficient was 6,11 for the inner muscular layer, 4,19 for the middle layer, and 6,63 for the outer layer. It was found that the increase in the thickness of the middle muscular layer was due to an increase in the volume of myocytes, and not their number. Abundant innervation and vascularization of the bladder wall of fetuses from the 16th week of gestation was detected. Summary. The morphological criteria for the degree of maturity of the bladder wall of the human fetus at different gestation periods were determined. They can be used to study the morphological characteristics of the detrusor formation in fetus pathology and congenital malformations of the urinary system.

Keywords

fetus / urinary bladder / morphometry / detrusor / myocytes

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RIGHTS & PERMISSIONS

Deryugina L.A., Maslyakova G.N., Rozkova D.V., Napsheva A.M.